Extensible aerial



April 22, 1941. c. w. MARTIN EXTENSIBLE AERIAL Filed Jan. 29, 1940 2Sheets-Sheet 1 I N VEN TOR.

CARY W.MART|N ATTORNEYS April 22, 1941- c. w. MARTIN EXTENSIBLE AERIAL 2Sheets-Sheet 2 Filed Jan. 29, 1940 22A FIG.8.

A 4 9 .0 B F A o 9 5 w M A F a 77/27/49 \D 1| I V v E A H Y7////////////INVENTOR.

CARYWMARTIN 1.1; 74 m? ATTOR lays Patented Apr. 22, 1941 2,239,614EXTENSIBLE AERIAL Gary W. Martin, Los Angeles, Calif.

Application January 29, 1940, Serial No. 316,153 12 Claims. 401150-43)This invention relates to extensible radio antennae, particularly formotor vehicles, having as its principal object the provision of animproved power-operated extensible and retractible i aerial which, whenretracted, is almost entirely concealed within the body of the vehicle,but

which is readily extensible, by the mere operation of a button-likecontrol located in the passenger compartment, to project to any desiredextent within its range of movement.

Aerials constructed in accordance with the present invention incorporatea cylindrical casing within which the antenna is housed when retracted,and within which a piston travels to actuate the aerial. The piston inturn is actuated, under the control of a valve, by means of suitablepres-sure changes, which may be derived from the intake manifold of theengine of the vehicle. In the operation of aerials of this class, it hasbeen difficult to keep water from entering the casing-cylinder, andthere short-circuiting the antenna. Since a reduced pressure existsinthe casing cylinder during operation of the aerial, a positive pressuredifference tends to force water 1 into the interior. It has been thepractice to pro-,

vide stuffing boxes at the point of emergence of the antenna rod, butthese cannot be completely air tight under all conditions, and the meansfor increasing the actuating pressure in,

vacuum within the cylinder accordingly has been i sufiicient to drawwater into the cylinder, in numerous instances. Inasmuch as a drop ortwo of water within the cylinder of such an aerial is sufficient todestroy its efiiciency, this difiiculty has been an extremely seriousone. An important object of the present invention, therefore, is toprovide improved and simplified means for positively preventing entranceof water to the cylinder of an antenna of the character indicated.Inasmuch as the room which is available within the body of modernmotorcars for installation of aerials of this class is very limited, itis necessary that the operating cylinders be of small diameter, and thisin turn limits the power available to operate the same if manifoldpressure is used as the motivating agency. It is accord ingly notfeasible to utilize tight stufling boxes, or other sealing means whichwould impose material resistance to movement of the rod, and a furtherand related object of the present invention is to provide means forpositively preventing entrance of water to the casing or cylinderwithout increasing the drag upon the antenna element and the powerrequired to operate the same.

Still another object-is to provide such an operative antenna having agrounded metallic casing cylinder which serves as an electrical shieldfor the antenna, when retracted or partly re- .tracted thereinto,preventing electrostatic and electromagnetic influences within theVehicle body from affecting radio reception, while at the same timeproviding an actuating cylinder for the antenna, the piston comprisingan insulating r member and cooperating with other insulating means toinsulate the antenna from the casing cylinder.

A further object is to provide improved means furnishing electrical andpneumatic connections 1 to the antenna and to the operating meanstherefor, the electrical connection being of such efficiency that undueelectrical losses, noises in the radio receiver and other troubles whichaccompany inefficient aerial connections are eliminated,

j despite the fact that a friction connection of the sliding type isemployed.

Still another object is to provide improved proportion to the size ofsuch an antenna, and to provide extremely simple and positive meanswhereby such an aerial of very compact proportions, consisting of aplurality of telescoping sections, may be projected and retracted in amanner rendering fully automatic the movement of all of such sections.

Other objects and advantages will be apparent from the followingdescription, wherein reference is made to the accompanying drawingsillustrating preferred embodiments of my invention and wherein similarreference numerals designate similar parts throughout the several views.

In the drawings:

Figure l is a fragmentary and somewhat diagrammatic view showing invertical section the forward portion of a motor vehicle equipped with anaerial constructed in accordance with the present invention.

Figure 2 is a longitudinal elevational view principally in substantiallydiametric cross section, but partly in side elevation, and centrallybroken away.

Figure 3 is a cross section taken substantially on the line 33 of Figure2, and looking in the direction of the arrows.

Figure 4 is a detail sectional view, on a larger scale, of a part of thetelescoping antenna element, showing the friction and contact means bywhich the extension portion is held against unwanted movement andmaintained in proper electrical contact with the outer section.

Figure 5 is a side elevational view of the control valve.

Figure 6 is an enlarged substantially diametric cross sectional viewthereof.

Figure 7 is a cross sectional view taken substantially on the line 1-1of Figure 6, and lookin in the direction of the arrows,

Figure 8 is a view similar to Figure 1, showing a somewhat modifiedconstruction.

Figure 9 is a longitudinal sectional view thereof, similar to Figure 2.

Figure 10 is a substantially diametric sectional view of the separatevacuum and pressure cylinder assembly which is employed to boost theactuating pressure in the modified embodiment; and

Figure 11 is a cross section taken substantially on the line of Figure9.

Referring now to the drawings:

Reference character |8 designates generally the body of a motor vehicle,which is illustrated fragmentarily and only in sufiicient detail toindicate the manner of installation of my improved antenna construction,inasmuch as the construction of the vehicle forms no part of my presentinvention. The vehicle is shown as provided with an engine l2 having anintake manifold I4, and an engine hood l5. A dash panel l1 separates theengine compartment from the passenger compartment, 28, and a cowl 22covers the portion of the passenger compartment forward of thewindshield. An instrument panel 25, located in the passengercompartment, serves to support a control valve 38 by which raising andlowering of the antenna is regulated.

A cylindrical casing 33 is provided, in which the antenna is housed whenretracted. Within the tubular casing pressure changes developed in theintake manifold of the engine are made to act upon a piston to move theaerial. The casing assembly may be mounted to project through anysuitable portion of the sheet metal sheathing of the vehicle body. Inthe shown arrangement it is hung from the cowl portion 22 at one side ofthe passenger compartment. When so positioned it is preferably locatedwithin the space between the inner and outer sheathing of the body. Theupper end of the antenna casing is reduced in diameter and projectsthrough the cowl, as shown in Figure 1, so that the antenna whenextended projects. above the car body, as indicated in dotted lines inFigure 1.

The details of construction of the antenna assembly are best shown inFigure 2. The cylindrical casing 33 is preferably a sheet metal tube, ofaluminum or the like, having a smooth interior surface and forming acylinder which is closed at its bottom by a cupped closure 35, and atits top by a head assembly comprising a body portion 31 formed of hardrubber or other suitable insulating material. The heads 35, 31 may bescrewed into the tube 33, as shown. A bore 38 in the head 31 is axiallyaligned with the cylinder 33 and guides a tubular antenna element 40,which at its lower end is attached to an actuating piston assembly. Thepiston assembly comprises two rigid sections designated 4|, 42 havingslidably interfitted central portions and formed of hard rubber,plastic, or other suitableinsulating material. Between the rigidsections 4|, 42 and spaced from the rod by the interfitted centralportions thereof is a soft packing member 43, of oil-treated leather orthe like, adapted to provide a tight seal with the Wall of the tube. Thepacking disc 43 is compressed between the discs 4|, 42 by a spring 44reacting against the discs and against an abutment pin 46 carried by theend of the piston rod portion upon which the piston assembly is mounted.Rod 45 will be seen to comprise an extension of the tubular antennaelement 48, to the end of which it is secured by interfitting grooveportions 41.

Two packing glands or stuffing boxes are provided in the head 31, onenear the bottom and the other near the top of the passage 38 throughwhich the aerial extends. The lower gland is generally designated 50,and is provided with a spring 5| which constantly tends to tighten thepacking. A similar gland is mounted in the nut by which the assembly issecured in place, the packing spring 56 being housed partly in the nutand partly in the counter-bored upper extremity 39 of the bore 38. Thusthe stuffing boxes are so located that one is outside the body and theother inside the body when the aerial is installed.

The tubular casing is adapted to be grounded to the vehicle body orchassis, as by the wire 34, and the shielding efiect is continuedupwardly to juncture with the cowl 22 by means of a sheet metal shieldcap 62 fitted over the head 37. Above and below the cowl 22, upon thereduced neck portion of the head, soft rubber fillers 64, 65 arearranged in such manner that they are compressed when the nut 60 istightened, and seal the aperture in the cowl through which the antennaassembly projects. A collar 66 above the top filler, 64, finishes theexterior and transmits the compressive eiiect of the nut, the reactionbeing taken against a shoulder 68 formed by the reduced diameter of theupper extremity of the head assembly. Collar 66 is also preferably ofinsulating material.

The bore 38 will be seen to fit the antenna snugly only at its upperend, adjacent the upper stuffing box 55, the rest of the bore beingenlarged to provide substantial clearance around the antenna elementthroughout the greater part of the distance between the two stuffingboxes. An aperture, 18, is formed in the side of the head 37, and itscap 62, to provide communication between the bore 38 and the spacebeneath the cowl. This opening is large enough to prevent reduction ofpressure in the passage 38, and thus breaks any vacuum which mightotherwise exist in the passage 38 due to leakage through the stuffingbox 58, and accordingly prevents any tendency to draw water or otherforeign matter through the upper stuffing box. This opening is of coursein a protected position, and will be seen to provide an escape for anywater which might find its Way through the upper stufi'ing box-althoughsuch leakage is almost impossible, in view of the equalized pressurewhich exists upon the two sides of the stufiing box 55.

Slidable in the antenna element 40 is a manually operable extension 48,which also may be of tubular construction. To the upper end of theextension a ball 49 is attached, forming both an ornament and aconvenient handle by which the extension may be grasped and pulled outor pushed into the main antenna element 40 at will. Frictional andelectrical contact between the extension section and the main antennatube 48 is provided by bifurcating the end of the extension section, asindicated at 12, and stressing the arms thus formed outwardly in suchmanner that they tend to expand against the interior of the antenna tube40. The extremities of the arms may also be rounded, as indicated at 13,

to insure smiooth wiping engagement, and their expanding, effort may bereinforced. by a rubber block 14, trapped between the arms in the space.

provided by the outwardly rounded sections, such rubber block acting asa spring for this purpose.

Electrical contact with the antenna assembly is furnished by springbrush fingers 15 carried by a supporting ringllmounted in the head 31,and loosely encircling the antenna. The ends of the spring fingers 15which engage the antenna are curved about a shorter radius .than that ofthe antenna tube 40, to provide reduced areas of engagement, andincrease the unit pressure between such fingers or brush members and theantenna rod. Brushes 15. may be formed of phosphor bronze, and unduewear of the rod is prevented by plating it with a hard chromium plating.This arrangement will be seen not only to provide materials of highconductivity, but to allow substantial pressure between the brushes andthe antenna, so that imperfect connections cannot develop. Thebrush-supporting ring 1'! is held by a hollow stud 80, threadedthereinto and projecting radially through the side of the antennacasing. Stud 80 serves as a binding post, the antenna lead-in wire 8|being connected thereto. The stud isinsulated from the portions 62, 33of the casing assembly by means of insulating-washers 82, 83. The hollowpost or stud80 and the connected end of the lead-in assembly will beseen to be housed in a shield can 85, from the s'ide of which thelead-ihwire extends to connection with the radio apparatus (unshown),through shielding loom 81, which is also suitably grounded.

The inner end of the hollow post 80 communicates with the space abovethe piston in the cylinder '33, and a rubber tube or other conduit 90 isconnected to the projecting outer end of the post, and extends throughan opening in is effected by means of a valve, the casing of which isgenerally designated 30, mounted upon the instrument panel of thevehicle and constructed in such manner that'the vacuum line 95 to theintake manifold is normally closed, but may be connected at will, bymovement'of the valve, toeither of the'tubes 90, 94, the formerconnected to the nipple 80 andthe latter to the nipple 92, aspreviouslydescribed' The valve body is designated 91, andwill be'seen tobe normally centered in the valve casing 30 by means of springs IOI,I02, arranged one at each end of the valve body.- A stem I03 and knobI04 attached to the valve body enable the same to be moved at will bythe operator against the efiort of the springs; Nipples I06, I01 and.I08 afford connection to the interior of the valve casing, their inneropenings being .adapted to be selectively connected by.means of a slot Hin the valve body. Travel of thevalve is limited by a pin and slotconnection I,II,'. II2. Vent apertures II 3, II4uare. provided inthelcasing at,

each endlof the valve, so that when the tubes 90, 94 which are connectedto each end of the cylinder are not connected to the intake manifold,they are vented to atmosphere. The pressure differential due to thevacuum normally existing in the intake manifold tends to draw the valvetightly against the side of the valve casing nearest nipple I01, and soseal the line 95, while the slot H0 is of such length and so positionedthat it may bridge only the distance required to connect either of thetubes 90, 94 to the vacuum line, 95.

It will be seen that when the valve is pushed in by means of the knobI04, connection of the vacuum to the tube results in a reduction ofpressure within the cylinder-.33 (while the space below the pistonremains connected to atmos- The phere through the tube 94 and vent III). antenna assembly is thereforelifted. When the valve is released itimmediately resumes the centered position shown in Figure 6, and theantenna assembly is held in whatever position it may then be in, by thefriction imposed by the stuffing boxes, brushes 15, and piston assembly.Lowe ering of the antenna assembly is effected in like manner by pullingthe valve .down to connect the vacuum line to tube 94. This will be seento effect a reduction of pressure below the piston, and to draw thepiston assembly down and return the aerial to the lowered position inwhich it is shown in full lines in Figures 1 and 2.

In the modified construction shown in Figures 8, 9 and 10, in whichparts equivalent to those already described have been givencorresponding reference numerals distinguished by the addition of theletter A to each, the tubular sheet metal casing 33A is adapted to besupported in similar fashion, to project through the cowl 22A or othersuitable portion of the vehicle. The casing 33A is grounded in similarfashion to act as a shield, and the telescoping aerial portions 40A, 48Aare extensible therefrom. In this embodiment, however, the inner orextension antenna section 48A is also equipped at its lower end withpiston sealing means, 433, while the piston assembly (generallydesignated 43A) of the outer extensible aerial section 40A, is providedwith a central aperture I25 extending therethrough to afford pressurecommunication permitting direct actuation of both sections of theantenna by pressure changes transmitted to the area below both thepistons, through coupling means 92A and conduit I26 connected thereto.-The coupling assembly will be seen to form a closure for the lower endof the cylinder.

The piston means 43A is constructed to insulate the antenna assemblyfrom the casing atthe lower end, while at the upper end of the assemblyinsulation is also provided by a sleeve 31A and insulating washer 31B ofsuitable material. At its upper end the aerial is secured in place by anut 60A containing a packing gland 55A which serves to seal the tubularantenna section 40A with respect to the cowl in a manner to preventinfiltration of water. A vent 10A is also provided in the side of thecasing tube 33A above the piston assembly but inside the body. This ventis of ample size to break any vacuum which might otherwise develop abovethe pistonv assembly 43A upon descent of the latter, thus preventing anytendency to draw water through the packing gland.

The central or extension antenna section48A is sealed with respect totheouter section 40A by means of a second gland I55, anda vent I10 isformed in the side of the antenna tube MA at a point which lies belowthe gland 55A when the aerial is fully retracted, air passages I60 beingformed in the insulating sleeve 31A to provide free communicationbetween vents 79A and H when the aerial sections are retracted. Thearrangement is such that when pressure is applied to the lower end ofthe casing, both pistons are raised at once, the extension sectionremaining fully retracted into the outer section until the latter isfully raised. When the outer section 40A has risen to its full height,however, continued pressure forces the central section outwardly toraise the extension. During the first stage of this double extension,the air above piston assembly 43A escapes through vent A, while duringthe second stage air above piston assembly 43B escapes through vent I10.When the pressure in the lower part of the casing is loweredsufficiently to cause retraction of the antenna sections, both sectionsfirst fall at once carrying the vent I10 down into the casing and belowthe gland 55A before the extension section 48A moves inwardly withrespect to the outer section 40A. Accordingly no air is drawn into thespace above piston assembly 433 until such air can enter from within thevehicle body through vent 10A and communicating passages I60. During thefirst stage of the downward movement air of course enters the spaceabove the piston assembly 43A through the vent 10A.

The pressure changes by which both sections of the antenna are projectedand retracted are generated in a special pressure cylinder I21, to whichconduit I26 is connected. A piston I30 in the pressure cylinder isoperable in response to pressure changes induced in a larger vacuumcylinder I33, attached at one end to the pressure cylinder in co-axialrelation therewith. A rod I34 connects piston I30 to a larger piston I35in the vacuum cylinder, and conduits 90A, 94A, connect opposite ends ofthe vacuum cylinder to the nipples IUBA, I08A, respectively of thecontrol valve, the casing of which is generally designated 30A.

The valve may be constructed similarly to the valve disclosed inconnection with the first described embodiment, the central nipple IU'lAthereof being connected to the intake manifold I SA of the engine IZA,by means of a vacuum conduit 95A. When the knob IBSA of the valve ispushed up, conduit 95A is connected to the vacuum line, and thereduction of pressure at the left side of piston I35 (as viewed inFigure 10), forces that piston to the left, and with it the piston I30.This increases the pressure in cylinder I21, and accordingly in thespace within cylinder 33A below both pistons. Both antenna sections arethus forced outwardly, to project them above the vehicle body to anydesired extent, in accordance with the increase of pressure. Air abovethe piston 43A, 43B is allowed to escape through vents I40, I4I. Whenthe valve is pulled down, reduction of pressure to the right of pistonI35 draws piston I30 in the same direction, reducing the pressure incylinder I21 and in the connected spaces below the pistons 43A, 43B,which are thus drawn into their respective tubes to retract the antennasections.

As shown in Figure 8, the pressure and vacuum cylinder assembly may bemounted principally in the engine compartment, as by supporting the samefrom the dash of the vehicle, the arrangement being shown as such thatonly the end of the pressure cylinder projects into the passengercompartment to a point adjacent the aerial. It will be recognized,however, that with this arrangement, the aerial might be located at aremote point, to project through the roof of the vehicle, for example,or at any other desired point. It will also be recognized that more thantwo extensible sections could be provided in like fashion. Extremecompactness is secured, in practical fashion, by reason of the fact thatit is possible to project and retract all sections by thepower-operating means, and the increased pressure provided by thebooster unit consisting of the pressure and vacuum cylinders, permitsuse of antenna tubes of smaller diameter than could be operated directlyby the vacuum developed in the intake manifold, at least against thedrag imposed by effective sealing means.

I am aware that the invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, and Itherefore desire the present embodiments to be considered in allrespects as illustrative and not restrictive; reference being had to theappended claims rather than to the foregoing description to indicate thescope of the invention.

What I claim is:

1. A radio aerial construction adapted to be supported within a vehiclebody portion, comprising a casing assembly including a metallic tube, aninsulating head portion closing the upper end of said tube, means forsupporting said casing assembly with its upper extremity extendingthrough and above a vehicle body portion, and with said insulating headportion projecting above and below the material of the body portion,said head having a passage extending longitudinally therethrough, anantenna element slidably extending through said passage and movableinwardly and outwardly with respect to the casing assembly but insulatedtherefrom by said head portion, piston means connected to an inner endof said antenna element Within the tube to actuate and guide the same,said inner end of the antenna element also being insulated from thetube, means for directing fluid under pressure against said piston toactuate the antenna element, stufling means located near the top of thecasing assembly but below the portion of the body portion through whichthe assembly projects, for sealing the antenna element with relationthereto, and a vent connecting the exterior of the casing assembly withthe passage in the head through which said antenna element extends, saidvent being located below said portion which is adapted to extend throughthe vehicle body, whereby the pressures in said passage above and belowsaid portion of the vehicle body may be neutralized.

2. A radio aerial construction adapted to be supported within a vehiclebody, comprising a casing assembly including a metallic tube and a headportion closing the upper end of said tube, means for supporting saidcasing assembly with its upper extremity extending through and above avehicle body, and with said head portion projecting above and below thematerial of the body, said head portion having a passage extendinglongitudinally therethrough, an antenna element slidably extendingthrough said passage and movable inwardly and outwardly with respect tothe casing assembly, pressure-operable means for actuating said antennaelement, stuffing means located near the top of the casing assembly butbelow said portion thereof which is adapted to project through thevehicle body, for

sealing said antenna element with respect to said passage and therebywith respect to the easing assembly, and a vent portion connecting theexterior of the casing assembly with said passage in the head, said ventalso being located below said portion which is adapted to extend throughthe vehicle body, whereby the pressures in said passage above and belowsaid portion of the vehicle are not influenced by' the pressure withinthe casing assembly below said stuffing means.

3. A radio aerial construction adapted to be supported within a vehiclebody, comprising a casing assembly including a metallic tube and aninsulating head portion closing the upper end of said tube, means forsupporting said casing as-- sembly with its upper extremity extendingthrough and above a vehicle body, an antenna element slidably extendingthrough said head portion and movable inwardly and outwardly withrespect to the casing assembly but insulated therefrom by said headportion, piston means also formed at least partly of insulating tojuncture with the vehicle body.

5. In an aerial construction as set forth in claim brush contact meanscarried by said head portion and wipingly engageable with said antennaelement, and lead-in contact means extending through and insulated fromthe grounded portions of said casing assembly and connected to saidbrush contact means.

6. In an aerial construction as set forth in claim 3 brush means carriedby said head portion and wipingly engageable with said antenna element,lead-in contact means extending through and insulated from the groundedportions of said casing assembly and connected to said brush means, saidmeans comprising a hollow connector opening at its inner end at a pointin communir cation with the interior of said casing assembly above saidpiston, and means for connecting a pressure-conducting conduit to theexterior of said connector.

7. In an aerial construction as set forth in claim 3, brush meanscarried by said head portion for providing electrical contact with saidantenna element, a hollow metallic connector extending through andinsulated from the grounded portions of said casing assembly andelectrically connected to said brush means, the innerend of saidconnector opening at a point in communication with the interior of saidcasing above said piston, said brush means being supported by the innerend of said connector, and means for making electrical and pressureconnections to the outer end of said connector.

8. In an extensible and retractible radio aerial, a plurality oftelescoping sections, a substantially pressure-tight casing enclosingthe lower end of the outer section, and means for applying variantpressures to said casing to enable selective projection and retractionof said sections,

comprising a vacuum cylinder having connections at opposite ends thereofand a piston adapted to travel thereinbetween said connections, apressure cylinder arranged substantially coax- -ially withrespect tosaid vacuum cylinder and of smaller diameter, a piston in said pressurecylinder, means providingmechanical connection .between said pistons;means providing pressure communication between the pressure cylinder andsaid casing, and valve means for selectively connecting said connectionsof the vacuum cylinder to a source of variant fluid pressure.

9. In a pressure-operated aerial construction, in combination with atubular casing adapted to be mounted in a vehicle body, said casinghaving a head portion adapted to project through and above the sheathingof the body, said head portion having a longitudinal passage therein, an

antenna element slidable in said passage inwardly and outwardly of thecasing to project to varying extent from a body in which the aerial isinstalled, two stufflng means in said passage, one arranged above andthe other below said portion of the head which is adapted to projectthrough the sheathing, said passage having a vent located at a pointabove the lower stufiing means but below said portion adapted to projectthrough said sheathing and connecting said passage to the exterior ofthe casing.

10. In an aerial construction as set forth in claim 3, electricalcoupling means carried by said head portion and adapted to conduct highfrequency energy between said antenna element and desired radioapparatus or the like, lead-in terminal means connected to said couplingmeans and adapted to be connected to such radio apparatus or the likeand extending through and insulated from the grounded portions of saidcasing assembly, said lead-in terminal means comprising a hollowconnector opening at its inner end at a point in communication with theinterior of said casing assembly above said piston, and means forconnecting a pressure-conducting conduit to the exterior of saidconnector.

11. In an aerial construction as set forth in claim 3, electricalcoupling means carried by said head portion and adapted to conduct highfrequency energy between said antenna element and desired radioapparatus or the like, a hollow metallic connector extending through andinsulated from the grounded portions of said casing assembly andelectrically connected to said electrical coupling means, the inner endof said connector opening at a point in communication with the interiorof said casing above said piston, said electrical coupling means beingsupported by the inner end of said connector, and means for makingelectrical and pressure connections to the outer end of said connector.

12. A radio aerial construction adapted to be supported by a vehiclebody and to project through a portion thereof, comprising a casingassembly including a tubular housing, a head portion substantiallyclosing the upper end of said housing but having a passage thereinadapted to slidably receive an antenna element, means for supportingsaid casing assembly with the upper end thereof extending through andwith said head extending above said vehicle body portion, an antennaelement slidably extending through said passage in the head portion andmovable inwardly and outwardly with respect to the. tubular housing andinsulated from the vehicle body, packing means operatively engaging theantenna element and the housing and located between said passage and theinterior of the housing to resist entrance of moisture into the housingalong the antenna element, and vent means connecting said passage at apoint above to said passage along the antenna element, to said packingmeans to the exterior of the casing prevent reduction of pressure at theupper end of assembly below that portion thereof which prosaid passagewhich communicates with the exjects through the vehicle body portion,whereterior of the body.

by said vent breaks any reduction of pressure Within the housing whichmay be communicated CARY W. MARTIN.

